This invention relates to vacuum cleaning devices and particularly to an improved air blower assembly for use in conjunction with liquid bath type vacuum cleaners.
Vacuum cleaners of various designs are used in residential and commercial settings for cleaning purposes. These appliances develop suction to create airflow which picks up particulates from the surface being cleaned. These particulates are separated from the air within the vacuum cleaner for later disposal. One type of vacuum cleaner is a so-called canister type which has a relatively stationary canister which is connected to a movable nozzle or wand by a flexible connecting hose. One design of canister type vacuum cleaners known as a liquid bath type directs incoming air and particulates into contact with a liquid bath which absorbs the particulate matter. Liquid bath vacuum cleaners have the significant advantage that their filtration mechanism uses readily available water, thereby eliminating the need for replaceable filters. These machines further provide a room humidifying effect since some water becomes dissolved in the air discharged from the vacuum cleaner during use.
Numerous designs of liquid bath type vacuum cleaners are presently known. For example, U.S. Pat. Nos. 2,102,353, 2,221,572, 2,886,127 and 2,945,553, all of which are assigned to the assignee of this invention, are related to various improvements in liquid bath type vacuum cleaners. Although devices constructed in accordance with the above-mentioned issued patents perform satisfactorily, designers are constantly seeking to reduce the noise level created by operation of vacuum cleaners. In order to provide a vacuum cleaner having satisfactory performance, high-powered air blowers are used to create the desired level of suction pressure with sufficient air flow rate capability necessary to remove entrapped, heavy, or minute particles. Such blower assemblies utilize rapidly rotating fan assemblies which generate noise which can constitute an annoyance to the user or others nearby. It has been found that high frequency noise is particularly undesirable. Designers of canister type vacuum cleaners are further continually attempting to improve the assembly techniques used in manufacturing these devices so that they can be produced at lower costs and with high precision. Present techniques employed to assemble the various elements making up the vacuum cleaner blower assembly lead to high labor costs since various components must be properly positioned, measured and adjusted in order to provide the necessary precision.
In view of the foregoing, it is an object of this invention to provide an improved blower assembly for vacuum cleaners. It is a further object of this invention to provide a blower assembly for a vacuum cleaner having improved sound attenuation features. It is yet another object of this invention to provide an improved blower assembly for vacuum cleaners which can be assembled quickly and accurately without requiring a high degree of operator skill and direct labor during production.
The above objects of this invention are provided by employing a series of fixed air flow directing vanes and barriers at the blower assembly inlet and outlet which serve to suppress the noise level generated by the internally rotating blower components. In part, such noise attenuation is achieved by directing the air to flow along a serpentine route at both the air inlet and outlet to prevent a straight uninterrupted path for the conduction of sonic waves. Improvement in the production assembly techniques are achieved by providing an improved upper stage assembly which features partial turn locking engagement with the motor base component which can be accomplished quickly yet provides a high degree of dimensional precision.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings.